first I would like to say sorry to you as I don't know if I'm writting in wrong section and also I'm not an Android user for last few months.

But now I want to buy one used phone and would like to see battery condition of it before buying, or actual capacity left and how much it lost with time, how much battery degraded over time and capacity reduced in mAh.

I know there is one, few nights ago I've been looking on net for LG G2 battery life and I've seen some guys posting screenshots ofsome app showing left battery capacity, but I didn't save it...